Sale 1: (outlier)

Sold for an Spec KS Australium FAN + 1 key

(13 + 1) = 14 keys

http://backpack.tf/profiles/76561198101578890?time=1438066800

http://backpack.tf/profiles/76561198101578890?time=1438412400

Sale 2:

Sold for a Professional KS Awper Hand

(24*0.9) = 21.6 rounding to 22 keys

http://backpack.tf/profiles/76561198101578890?time=1436252400

http://backpack.tf/profiles/76561198101578890?time=1436338800

Sale 3:

Sold with 2 TODs for a DBD Merry Weather

(30*0.9) - 1 = 26 keys

http://backpack.tf/profiles/76561198014404374?time=1438412400

http://backpack.tf/profiles/76561198014404374?time=1438585200

Notes:

Mini for the Awper Hand ~24

http://www.tf2outpost.com/trade/26655309 Unsold at 24 for a week, capping its price based on this

Mini for the Australium FAN ~13

http://backpack.tf/classifieds?item=Force-A-Nature&quality=11&tradable=1&craftable=1&australium=1&killstreak_tier=2

Sellers at 13, bp.tf price is wayyyy too inflated

Conclusion:

22 to 26 keys